Listen I have been this for 5 hours straight I am a poor math student but I try. My teacher is rude and ignorant. Please if it is not to much trouble a little help please. Currently I have no patience.
I'll do the first one.
(1) a+4b=15
(2) 5b=2a+3
Isolate for either "a" or "b" in (1) or (2).
I'll isolate for "a" because it's easier.
(1) a = 15 - 4b
(2) 5b = 2a + 3
Now, substitute (1) into (2) to find "b"
5b = 2a + 3
5b = 2(15 - 4b) + 3
5b = 30 - 8b + 3
Isolate for "b"
5b + 8b = 33
13b = 33
b = 33/13
Now, substitute "b = 33/13" into (1) or (2) to find "a"
a = 15 - 4b
a = 15 - 4(33/13)
a = 15 - 132/13
Need a common denominator
a = (195 - 132)/13
a = 63/13